The present invention relates to a method of machining parts using CNC (computerized numerical control) machinery and techniques.
Parts are machined using CNC techniques and machinery. CNC techniques and machinery are well known. The structural and shape details of the part to be formed are programmed into a computer which operates various components of a CNC machining apparatus. Following the programmed design criteria, the CNC machining apparatus will machine a part to size and shape. Typically, this will involve the use of multiple cutting tools or devices following various programmed cutting tracks which may be straight, stepped, curved, compound and the like. Reference points are provided for the CNC machining apparatus components to orient and position themselves during cutting tool changes and machining track changes.
CNC machining is commonly used to form patterns, tools, prototype parts and production parts out of various materials that are dimensionally stable enough to be machined with a desired degree of accuracy and finish. However, the formed part is as it is finished, with the properties of the machine formed part the same as those of the starting material. Additional finishing steps may be performed later, e.g., polishing and heat treating. Thus, if a highly durable end product is needed, the starting material needs to be highly durable. This increases the expense of the machined part typically because higher density, harder more durable materials increases the material and machining costs. It would be desirable, to provide a method of forming a CNC formed part which would allow subsequent changing of the properties of the formed part in an easy manner to provide increased durability on at least the machined and exposed part surface but allow the use of a cost effective substrate material which often times is easier to machine to shape. However, the resulting end product should be predictably dimensioned to the desired dimensions and tolerances.
The prior art process of forming pattern parts using CNC machining typically includes part design, creating machining instructions, pattern cutting or fabrication, pattern surface preparation for tool construction, and prototype or production tool fabrication of a pattern surface. When the pattern material used is of a very low density it is not uncommon to destroy or damage the pattern during the fabrication of a single production tool, e.g., a mold component. When that happens, and more production tools are needed, a master tool is fabricated from the original production tool and subsequent production tools are built off the master tool. Such a process is time consuming and expensive. The present invention provides an improvement to this process and produces a durable tool or part that can be used as an end part or a pattern which has increased durability utilizing a relatively inexpensive easy to machine and porous substrate.
The present invention provides such a process and resulting end product.